Manual tensioner bolt ruined - how do I get it out

Changing a headgasket on a mates 1.4 Rover 200 and the hex bolt on the tensioner is well and truly stuffed. It is pretty much round inside and it looks like someone has tried unsuccessfully to weld a nut to it.



The tensioner needs replacing anyway because it is pretty noisy.



Has anyone had this before? I am tempted to drill the head off but i'm worried that I'll be left with a stud that I can't move. I'm hoping that once its not in tension it might come out with mole grips.



Not sure what else I can do. Any advice? Needs to be cheap because I've been set a budget of £50 and the headgasket and tensioner and bolt will take up most of that. I'm doing it for free, other problem is she wants it back by thursday!

from the last news http://ift.tt/1ntVcR6

via IFTTT